Question

If you burn 51.4g of of hydrogen and produce 459g of water, how much oxygen reacted?

Answer 1

old question but will answer so this can be closed

2H2 + O2 --> 2H2O
start with 459g of water, divide by the molar mass of water to convert to moles, use the equation to convert to moles of oxygen, multiply moles O2 by the molar mass of O2 to convert to grams O2